Solid-state image capturing apparatus, driving method of the solid-state image capturing apparatus, and electronic information device

ABSTRACT

A solid-state image capturing apparatus includes a plurality of pixel sections, a vertical transfer section, and a horizontal transfer section, wherein the horizontal transfer section includes a plurality of transfer gates consecutively arranged in a horizontal direction and a signal wiring for supplying a driving signal to the transfer gates, and wherein a layout pattern of at least one layer of constituent members which constitute the horizontal transfer section is a pattern in which the transfer gates and the signal wiring are connected so that electric charge transfer directions become opposite from each other on both sides of a branching position in the horizontal transfer section.

This nonprovisional application claims priority under 35 U.S.C. §119(a)to Patent Application No. 2007-282488 filed in Japan on Oct. 30, 2007,the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a solid-state image capturingapparatus, a driving method of the solid-state image capturingapparatus, and an electronic information device. In particular, thepresent invention relates to a solid-state image capturing apparatus, inwhich a charge transferring direction of a horizontal transfer sectionis configured to be reversed on both sides of a predetermined position;a driving method of the solid-state image capturing apparatus; and anelectronic information device.

2. Description of the Related Art

In general, a solid-state image capturing apparatus transfers electriccharges generated by photoelectric conversions in a plurality of pixelsections (also simply referred to as a pixel, hereinafter) arranged in atwo dimensional array by a vertical transfer section corresponding toeach pixel section column in the vertical direction for each individualpixel section. The solid-state image capturing apparatus subsequentlytransfers the electric charges from the vertical transfer section by ahorizontal transfer section, which is positioned at one end side of thevertical transfer section, to the horizontal direction for each line tobe sent to an output section, and the solid-state image capturingapparatus outputs the electric charges as image capturing signals fromthe output section.

When capturing a video, the transferring of an electric charge from alight receiving section (pixel section) to an output section needs to becompleted within a certain period of time in accordance with a framerate, and the transferring of an electric charge requires a sufficientperiod of time so as not to cause deterioration due to the transferring.Therefore, it is required for a period of time for both the verticaltransfer and the horizontal transfer to be set in view of the efficiencyof the transfer.

In addition, a common solid-state image capturing apparatus has aconfiguration in which electric charges of all the effective pixels aretransferred in the vertical direction, and subsequently, the electriccharges are transferred in the horizontal direction to be sent to anoutput section. Therefore, such a solid-state image capturing apparatusis required for transferring electric charges with the same amount oftime for all the effective pixels or for electric charges of a pixel ofone frame even when the number of pixels required for capturing an imageis smaller than the number of effective pixels.

For such a problem, Reference 1 discloses a method for, by providing ahorizontal CCD drain gate between a horizontal CCD, which is ahorizontal charge transfer section, and a horizontal CCD drainpositioned near the horizontal CCD along the transfer direction,sweeping out unnecessary electric charges at once from the horizontalCCD to the horizontal CCD drain.

FIG. 9 is a diagram illustrating a method disclosed in Reference 1described above, which illustrates a solid-state image capturingapparatus according to this method.

A solid-state image capturing apparatus 200 includes: a plurality ofpixel sections 1 positioned in a matrix for photoelectrically convertingan incident light into a signal charge; a vertical transfer section 2for reading out the signal charge stored in each of the pixel sections 1to transfer it in a column direction (vertical direction); a horizontaltransfer section 3 for transferring the signal charge from the verticaltransfer section 2 in a row direction (horizontal direction); and anoutput section 4 for amplifying the transferred signal charge andoutputting it as an image capturing signal. Herein, the verticaltransfer section 2 described above is positioned for each column ofpixel sections and along each column of pixel sections, and thehorizontal transfer section 3 described above is positioned at one endside of the vertical transfer section 2. In addition, a horizontalsweeping drain 6 is positioned on the opposite side of the horizontaltransfer section 3 from a positional area of the pixel section describedabove, and a horizontal CCD drain gate 24 is positioned between thehorizontal sweeping drain 6 and the horizontal transfer section 3. Inaddition, a vertical sweeping drain 5 is positioned on the opposite endof the vertical transfer section 2 described above.

Next, an operation will be described.

Herein, the center portion of the effective pixel area (i.e., areahaving pixel sections arranged in a matrix therein) in the solid-stateimage capturing apparatus is defined as a desirable image cutting outarea 25. Therefore, electric charges generated in areas A and B areunnecessary electric charges, the area A being positioned above theupper end position of the pixel cutting out area 25 and the area B beingpositioned below the lower end position of the pixel cutting out area25. Similarly, electric charges generated in areas C and D areunnecessary electric charges, the areas C and D being positioned on theleft and right sides of the pixel cutting out area 25.

According to the conventional technique, when the unnecessary electriccharges generated in the areas A and B are vertically transferred, thehorizontal CCD drain gate 24 is turned on, and the unnecessary electriccharges transferred to the horizontal transfer section 3 is drained tothe horizontal sweeping drain 6 without being transferred in thehorizontal direction. Further, unnecessary electric charges generated inthe areas C and D and electric charges for one line including necessaryelectric charges generated in the desired pixel cutting out area 25, arevertically transferred to the horizontal transfer section. Subsequently,when the electric charges transferred in the horizontal transfer sectionis horizontally transferred, necessary electric charges 20 generated inthe desirable pixel cutting out area 25 are transferred to the outputsection 4 subsequent to unnecessary electric charges 21 generated in thearea C, and the horizontal CCD drain gate 24 is turned on to drain theunnecessary electric charges to the horizontal sweeping drain 6. As aresult, among all the electric charges generated in the entire effectivepixels of an image capturing element, unnecessary electric charges arethrown away, making it possible to reduce a driving frequency of ahorizontal CCD functioning as a horizontal transfer section.

Reference 1: Japanese Laid-Open Publication No. 11-8801

SUMMARY OF THE INVENTION

According to the conventional technique described above, however, it isrequired to drive the horizontal CCD drain gate 24 at a predeterminedtiming so as to effectively transfer electric charges generated in thedesirable area (pixel cutting out area) of the effective pixel area.Therefore, a signal terminal is required for applying such a drivingsignal to the horizontal CCD drain gate 24. Further, a driving circuitis also required for generating a driving timing pattern of the gate,namely a driving signal. As a result, the number of the terminals willincrease and another circuit will be added for creating the drivingtiming pattern, resulting in the expansion of the circuit configuration.

The present invention is intended to solve the conventional problemsdescribed above. The objective of the present invention is to provide asolid-state image capturing apparatus, a driving method of thesolid-state image capturing apparatus, and an electronic informationdevice using the solid-state image capturing apparatus, where thesolid-state image capturing apparatus includes a transfer branchingposition of an area for transferring electric charges as necessaryelectric charges in a predetermined direction and an area fortransferring electric charges in a reverse direction, the transferbranching position being able to be arbitrarily set by a layout patternfor members to constitute the horizontal transfer section, so thatnecessary electric charges can be effectively transferred by the drivingof the horizontal transfer section, and further, the driving frequencyof the horizontal CCD can be reduced at the time of reading out thenecessary electric charges from a partial area of the effective pixelarea without adding another circuit configuration for sweeping outunnecessary electric charges.

A solid-state image capturing apparatus according to the presentinvention includes: a plurality of pixel sections positioned in an arrayfor photoelectrically converting an incident light into a signal charge;a vertical transfer section for transferring the signal charge read outfrom each of the pixel sections in a vertical direction; and ahorizontal transfer section for transferring the signal chargetransferred from the vertical transfer section in a horizontaldirection, wherein the horizontal transfer section includes a pluralityof transfer gates consecutively arranged in a horizontal direction, anda signal wiring for supplying a driving signal to the transfer gates,wherein a layout pattern of at least one layer of constituent membersconstituting the horizontal transfer section is a pattern in which thetransfer gates and the signal wiring are connected so that electriccharge transfer directions become opposite from each other on both sidesof a branching position in the horizontal transfer section, therebyachieving the objective described above.

Preferably, in a solid-state image capturing apparatus according to thepresent invention, the horizontal transfer section includes: a firsttransfer electrode configured of two adjacent transfer gates and drivenby a first driving signal; a second transfer electrode formed of twoadjacent transfer gates and driven by a second driving signal, which hasa reversed phase from the first driving signal; a first signal wiringfor supplying the first driving signal to the transfer gates thatconfigure the first transfer electrode; and a second signal wiring forsupplying the second driving signal to the transfer gates that configurethe first transfer electrode.

Still preferably, in a solid-state image capturing apparatus accordingto the present invention, the first signal wiring and the second signalwiring are formed by patterning a same metal layer.

Still preferably, in a solid-state image capturing apparatus accordingto the present invention, the first signal wiring is formed bypatterning a first metal layer, and the second signal wiring is formedby patterning a second metal layer, which is different from the firstmetal layer.

Still preferably, in a solid-state image capturing apparatus accordingto the present invention, a layout pattern of the first and secondsignal wirings is a pattern in which the transfer gates and the signalwiring are connected so that electric charge transferring directions areopposite from each other on both sides of a predetermined position inthe horizontal transfer section.

Still preferably, in a solid-state image capturing apparatus accordingto the present invention, one of the two adjacent transfer gates thatconfigure the first transfer electrode is formed by patterning a firstpolysilicon layer, and the other of the two adjacent transfer gates isformed by patterning a second polysilicon layer different from the firstpolysilicon layer, one of the two adjacent transfer gates that configurethe second transfer electrode is formed by patterning the firstpolysilicon layer, and the other of the two adjacent transfer gates isformed by patterning the second polysilicon layer.

Still preferably, in a solid-state image capturing apparatus accordingto the present invention, the four transfer gates that configure theadjacent first and second transfer electrodes are first to fourthtransfer gates consecutively arranged in a horizontal direction, and thefirst to fourth transfer gates have different plan view forms.

Still preferably, in a solid-state image capturing apparatus accordingto the present invention, on one side of a predetermined position in thehorizontal transfer section, the first transfer electrode is configuredof the first and second transfer gates and the second transfer electrodeis configured of the third and fourth transfer gates; and on the otherside of a predetermined position in the horizontal transfer section, thefirst transfer electrode is configured of the second and third transfergates and the second transfer electrode is configured of the fourth andfirst transfer gates.

Still preferably, in a solid-state image capturing apparatus accordingto the present invention, a layout pattern of a plurality of transfergates that configure the first and second transfer electrodes is apattern in which the transfer gates and the signal wiring are connectedso that electric charge transferring directions become opposite fromeach other on both sides of a predetermined position in the horizontaltransfer section.

Still preferably, in a solid-state image capturing apparatus accordingto the present invention, one of the two adjacent transfer gates thatconfigure the first transfer electrode is formed by patterning a firstpolysilicon layer, and the other of the two adjacent transfer gates isformed by patterning a second polysilicon layer different from the firstpolysilicon layer, and wherein one of the two adjacent transfer gatesthat configure the second transfer electrode is formed by patterning thefirst polysilicon layer, and the other of the two adjacent transfergates is formed by patterning the second polysilicon layer.

Still preferably, in a solid-state image capturing apparatus accordingto the present invention, the four transfer gates that configure theadjacent first and second transfer electrodes are first to fourthtransfer gates consecutively arranged in a horizontal direction, thefirst transfer gate and the third transfer gate having the same planview form, and the second transfer gate and the fourth transfer gatehaving the same plan view form.

Still preferably, in a solid-state image capturing apparatus accordingto the present invention, on one side of a predetermined position in thehorizontal transfer section, the first transfer electrode is configuredof the first and second transfer gates and the second transfer electrodeis configured of the third and fourth transfer gates; and on the otherside of a predetermined position in the horizontal transfer section, thefirst transfer electrode is configured of the second and third transfergates and the second transfer electrode is configured of the fourth andfirst transfer gates.

Still preferably, a solid-state image capturing apparatus according tothe present invention further includes an output section positioned oneither of one end side or the other end side of the horizontal transfersection, for outputting a signal charge from the horizontal transfersection as an image capturing signal, wherein the horizontal transfersection transfers unnecessary electric charges from the verticaltransfer section in an opposite direction of the output section from thebranching position.

Still preferably, a solid-state image capturing apparatus according tothe present invention further includes a first output section positionedon one end side of the horizontal transfer section for outputting asignal charge from the horizontal transfer section as an image capturingsignal; and a second output section positioned on the other end side ofthe horizontal transfer section for outputting a signal charge from thehorizontal transfer section as an image capturing signal.

Still preferably, in a solid-state image capturing apparatus accordingto the present invention, the branching position is set at an arbitraryposition in the horizontal transfer section by changing one or morelayers of a layout pattern of constituent members that constitute thehorizontal transfer section.

Still preferably, in a solid-state image capturing apparatus accordingto the present invention, mask patterns other than mask patternscorresponding to the changed layout pattern are shared among solid-stateimage capturing apparatuses having the different branching positions.

Still preferably, a solid-state image capturing apparatus according tothe present invention further includes a horizontal drain positioned onthe opposite side of the output section of the horizontal transfersection, for sweeping out the unnecessary electric charges.

Still preferably, in a solid-state image capturing apparatus accordingto the present invention, the horizontal transfer section is configuredto set the predetermined position by the layout pattern for theconstituent members which constitute the horizontal transfer section, sothat pixel sections with fewer than the number of the effective pixels,which is the number of the plurality of pixel sections positioned in anarray, is used as pixel sections that constitute an image capturingarea.

Still preferably, in a solid-state image capturing apparatus accordingto the present invention, a layout pattern of the constituent memberswhich constitute the horizontal transfer section is any of a layoutpattern of the transfer gates, a layout pattern of the signal wiring,and a layout pattern of a contact layer connecting the transfer gatesand the signal wiring.

Still preferably, in a solid-state image capturing apparatus accordingto the present invention, the horizontal transfer section drives thetransfer gates by a driving signal of three phases or more.

A driving method according to the present invention drives thesolid-state image capturing apparatus described above, in which adriving signal is supplied to a plurality of transfer gates in ahorizontal transfer section in the solid-state image capturingapparatus, so that, on one side of a branching position of thehorizontal transfer section, electric charges from the vertical transfersection are transferred as necessary electric charges to a signalprocessing section positioned on one end side of the horizontal transfersection, and on the other side of the branching position of thehorizontal transfer section, electric charges from the vertical transfersection are transferred as unnecessary electric charges to an electriccharge sweeping section positioned on the other end side, therebyachieving the objective described above.

A driving method according to the present invention drives thesolid-state image capturing apparatus described above, in which adriving signal is supplied to a plurality of transfer gates in ahorizontal transfer section in the solid-state image capturingapparatus, so that, on one side of a branching position of thehorizontal transfer section, electric charges from the vertical transfersection are transferred as necessary electric charges to a first signalprocessing section positioned on one end side of the horizontal transfersection, and on the other side of the branching position of thehorizontal transfer section, electric charges from the vertical transfersection are transferred as necessary electric charges to a second signalprocessing section positioned on the other end side, thereby achievingthe objective described above.

An electronic information device according to the present inventionincludes an image capturing section, wherein the image capturing sectionincludes the solid-state image capturing apparatus according to thepresent invention, thereby achieving the objective described above.

Hereinafter, the function of the present invention will be described.

According to the present invention, in a horizontal transfer sectionincluding a plurality of transfer gates consecutively arranged in thehorizontal direction and a signal wiring for providing a driving signalfor the transfer gates, a layout pattern of at least one layer of themembers that constitute the horizontal transfer section is defined to bea pattern to connect the transfer gates and the signal wiring so thatthe electric charge transferring directions will be opposite from eachother on both sides of the branching position in the horizontal transfersection. Therefore, the position for transferring electric charges forhorizontal transferring to the left and right directions can bearbitrarily set by a change of one or more layers of the layout pattern.In addition, an output section is positioned on one terminal side of thehorizontal transfer section and a sweeping drain is positioned on theother terminal side, and electric charges are transferred to either theoutput section or the sweeping drain, in such a manner, for example,that necessary electric charges are transferred to the output sectionand unnecessary electric charges are transferred to the sweeping drain,so that a horizontal transfer period can be conserved and a horizontaldriving frequency can be reduced without dropping the frame rate.

As a result, the driving frequency of the horizontal CCD can be reducedat the time of reading out necessary electric charges from a partialarea in the effective pixel area, without additionally adding a circuitconfiguration for sweeping out unnecessary electric charges, namely aterminal for applying a driving signal to an electric charge sweepingdrain gate and a circuit for creating the driving signal.

In the solid-state image capturing apparatus described above accordingto the present invention, the horizontal transfer section is configuredto set the predetermined position by the layout pattern for the membersto constitute the horizontal transfer section, so that pixel sectionswith fewer than the number of the effective pixels, which is the numberof the plurality of pixel sections positioned in an array, will be usedas pixels that constitute the image capturing area. As a result, theswitching to a solid-state image capturing apparatus which uses pixelsfewer than the number of effective pixels for capturing an image can beachieved by the change of one or more layers of the layout pattern.

In the solid-state image capturing apparatus described above accordingto the present invention, the layout pattern for the members toconstitute the horizontal transfer section is any of the layout patternfor the transfer gate, the layout pattern for the signal wiring and thelayout pattern for a contact layer that connects the transfer gate andthe signal wiring. Therefore, the position for transferring electriccharges to the left and right can be arbitrarily set by the change of ametal wiring layer as the signal wiring, a contact layer, or apolysilicon layer that constitute the transfer gate.

According to the present invention with the configuration describedabove, a transfer branching position of an area for transferringelectric charges as necessary electric charges in a predetermineddirection and an area for transferring electric charges as unnecessaryelectric charges in a reverse direction, can be arbitrarily set insidethe horizontal transfer section in the solid-state image capturingapparatus by the layout pattern for the members to constitute thehorizontal transfer section. As a result, necessary electric charges canbe effectively transferred by the driving of the horizontal transfersection, and further, the driving frequency of the horizontal CCD can bereduced at the time of reading out the necessary electric charges from apartial area of the effective pixel area without adding another circuitconfiguration for sweeping out unnecessary electric charges.

These and other advantages of the present invention will become apparentto those skilled in the art upon reading and understanding the followingdetailed description with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view illustrating a solid-state image capturingapparatus according to Embodiment 1 of the present invention.

FIG. 2 is a diagram explaining a specific configuration of a horizontaltransfer section in the solid-state image capturing apparatus accordingto Embodiment 1. FIG. 2( a) illustrates a layout of a transfer gate anda wiring in the horizontal transfer section. FIGS. 2( b) and 2(c)illustrate a plan view form of a transfer gate in a first layer.

FIG. 3 is an illustrative diagram of the solid-state image capturingapparatus according to Embodiment 1, illustrating a timing chart of adriving pulse applied to the transfer gate in the horizontal transfersection of the solid-state image capturing apparatus.

FIG. 4 is a diagram illustrating a cross sectional structure along theline IIA-IIA′ in FIG. 4 and a potential distribution in the horizontaltransfer section.

FIG. 5 is a diagram explaining a solid-state image capturing apparatusaccording to Embodiment 2. FIG. 5( a) illustrates a layout of a transfergate and a wiring in a horizontal transfer section. FIGS. 5( b) and 5(c)illustrate a plan view form of a transfer gate in a first layer.

FIG. 6 is a diagram explaining a solid-state image capturing apparatusaccording to Embodiment 3, illustrating a layout of a transfer gate anda wiring in a: horizontal transfer section.

FIG. 7 is a diagram explaining a solid-state image capturing apparatusaccording to Embodiment 3. FIGS. 7( a) and 7(b) illustrate a plan viewform of a transfer gate in a first layer in a horizontal transfersection. FIG. 7( c) illustrates a plan view form of a transfer gate in asecond layer.

FIG. 8 is a block diagram illustrating an exemplary diagrammaticstructure of an electronic information device, as Embodiment 4 of thepresent invention, using the solid-state image capturing apparatusaccording to any of Embodiments 1 to 3 of the present invention as animage input device in an image capturing section.

FIG. 9 is a diagram explaining a method disclosed in Reference 1,illustrating a solid-state image capturing apparatus adopting thismethod.

-   -   1 pixel section    -   2 vertical transfer section    -   3 horizontal transfer section    -   4 output section    -   5 vertical sweeping drain    -   25 pixel cutting out area    -   100 solid-state image capturing apparatus    -   103, 203, 303 horizontal transfer section    -   106 horizontal sweeping drain    -   X transfer branching boundary (transfer branching position)

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present invention will be described withreference to the accompanying figures.

Embodiment 1

FIG. 1 is a schematic view illustrating a solid-state image capturingapparatus according to Embodiment 1 of the present invention.

A solid-state image capturing apparatus 100 according to Embodiment 1includes: a plurality of pixel sections 1 positioned in a matrix forphotoelectrically converting an incident light into a signal charge; avertical transfer section 2 for reading out the signal charge stored ineach of the pixel sections 1 to transfer it in a column direction(vertical direction); a horizontal transfer section 103 for transferringthe signal charge from the vertical transfer section 2 to a rowdirection (horizontal direction); and an output section 4 for amplifyingthe transferred signal charge and outputting it as an image capturingsignal. Herein, the vertical transfer section 2 described above ispositioned for and along each column of pixel sections, and thehorizontal transfer section 103 described above is positioned at one endside of the vertical transfer section 2. In addition, a verticalsweeping drain 5 is positioned on the opposite side of the verticaltransfer section 2. Such a configuration is the same as theconfiguration of the conventional solid-state image capturing apparatus200.

In addition, according to Embodiment 1, a horizontal sweeping drain 106is positioned on the lower side of the horizontal transfer section 103described above, namely on the opposite side of a positional area forthe pixel sections 1 described above. The horizontal sweeping drain 106has an L-letter shape in a plan view, being configured with a transverseportion along a lower edge of the horizontal transfer section 103 and alongitudinal portion along the right side edge of the horizontaltransfer section 103 opposite from the output section 4.

In addition, the horizontal transfer section 103 described above isconfigured with a transfer branching boundary X (referred to as atransfer branching position, hereinafter) at a position corresponding tothe right side in the figure of the pixel cutting out area 25 in theeffective pixel area.

Specifically, the horizontal transfer section 103 includes a firsttransfer section 103 a positioned on the output section 4 side (leftside in the figure) of the transfer branching boundary X and a secondtransfer section 103 b positioned on the opposite side (right side inthe figure) from the output section 4 of the transfer branching boundaryX. Herein, the first transfer section 103 a described above is a CCDsection for transferring electric charges transferred from the verticaltransfer section 2 to the output section 4 side as necessary electriccharges. The second transfer section 103 b described above is a CCDsection for transferring electric charges transferred from the verticaltransfer section 2 to the longitudinal portion of the horizontalsweeping drain 106 described above as unnecessary electric charges.

FIGS. 2 to 4 are diagrams illustrating specific configurations of thehorizontal transfer section 103. FIG. 2 illustrates a layout of atransfer gate and a wiring of the horizontal transfer section 103. FIG.3 illustrates a timing chart of driving pulses applied to the transfergate. FIG. 4 illustrates a cross sectional structure along the lineIIA-IIA′ in FIG. 2 and a potential distribution in the horizontaltransfer section 103.

As illustrated in FIG. 2( a), the horizontal transfer section 103 isarranged therein with a plurality of transfer gates 14 a, 14 b, 15 a and15 b consecutively and repetitively in the horizontal transfer directionfor transferring electric charges transferred from the vertical transfersection 2 in the horizontal direction.

Herein, the transfer gates 14 a and 14 b are transfer gates in the firstlayer, the transfer gates being formed by placing a first polysiliconfilm using a mask pattern. Further, the transfer gates 15 a and 15 b aretransfer gates in the second layer, the transfer gates being formed byplacing a second polysilicon film positioned above the first polysiliconfilm using a mask pattern.

In addition, a first driving pulse a φH1 is applied to the transfergates 14 a and 15 a, and a second driving pulse φH2 is applied to thetransfer gates 14 b and 15 b. That is, according to Embodiment 1 of thepresent invention, the horizontal transfer section 103 is configured totransfer signal charges of one packet by two-phase gates, to which thefirst and second driving pulses φH1 and φH2 are applied.

In detail, the transfer gate 15 b in the second layer is positioned in atransfer branching position X of the horizontal transfer section 103. Inaddition, the transfer gate 15 a in the second layer, the transfer gate14 a in the first layer, the transfer gate 15 b in the second layer, andthe transfer gate 14 b in the first layer are repetitively arranged inthe first horizontal CCD section 103 a positioned on one side of thetransfer branching position X, for transferring electric charges to theoutput section 4, in this order towards the direction to which electriccharges are transferred (left direction in the figure). Further, thetransfer gate 15 a in the second layer, the transfer gate 14 a in thefirst layer, the transfer gate 15 b in the second layer, and thetransfer gate 14 b in the first layer are repetitively arranged in thesecond horizontal CCD section 103 b positioned on the other side of thetransfer branching position X for transferring electric charges towardsthe sweeping drain 106, in this order towards the direction to whichelectric charges are transferred (right direction in the figure).

Further, in an electric charge transfer area 103 c for transferringelectric charges below the transfer gates 15 a and 15 b in the secondlayer, a diffusion area 19 is formed for orienting an electric field sothat a transferring direction is determined for transferring electriccharges when the driving pulse described above is applied.

On the side of one end of the transfer gates, wirings 10 and 11 arepositioned for supplying a two-phase driving pulse of each of thetransfer gates described above. The wirings are formed by placing metalfilms formed in a pattern with an insulation film interposed above apolysilicon film forming the transfer gates described above. The wiringsare connected to each of the transfer gates through a contact hole thatpenetrates the insulation film.

That is, in the first horizontal CCD section 103 a on the one side (leftside in the figure) of the transfer branching position X, the transfergate 15 a in the second layer and the transfer gate 14 a in the firstlayer positioned on the left side and adjacent to the transfer gate 15 aare connected respectively via contacts 16 a and 16 b to the metalwiring 10 that supplies the first driving pulse φH1, and the transfergate 15 b in the second layer and the transfer gate 14 b positioned onthe left side and adjacent to the transfer gate 15 b are connectedrespectively via contacts 17 a and 17 b to the metal wiring 11 thatsupplies the second driving pulse φH2. As a result, in the firsthorizontal CCD 103 a, the transfer gate 15 a in the second layer and thetransfer gate 14 a in the first layer positioned on the left side form aφH1 transferring electrode 12, and the transfer gate 15 b in the secondlayer and the transfer gate 14 b positioned on the left side form a φH2transferring electrode 13.

On the other hand, in the second horizontal CCD section 103 b on theother side (right side in the figure) of the transfer branching positionX, the transfer gate 15 a in the second layer and the transfer gate 14 ain the first layer positioned on the right side and adjacent to thetransfer gate 15 a are connected respectively via contacts 16 a and 16 bto the metal wiring 10 that supplies the first driving pulse φH1, andthe transfer gate 15 b in the second layer and the transfer gate 14 bpositioned on the right side and adjacent to the transfer gate 15 b areconnected respectively via contacts 17 a and 17 b to the metal wiring 11that supplies the second driving pulse φH2. As a result, in the secondhorizontal CCD 103 b, the transfer gate 15 a in the second layer and thetransfer gate 14 a in the first layer positioned on the right side forma φH1 transferring electrode 12, and the transfer gate 15 b in thesecond layer and the transfer gate 14 b positioned on the left side forma φH2 transferring electrode 13.

In addition, in the transfer branching position X, the transfer gate 15b in the second layer positioned on the transfer branching position X isconnected by the contact 17 b to the metal wiring 11 that supplies thesecond driving pulse φH2. The transfer gate 14 b, which is positioned onthe left side of the transfer gate 15 b positioned on the transferbranching position X, is connected by the contact 17 a to the metalwiring 11. The transfer gate 14 b, which is in the first layerpositioned on the right side of the transfer gate 15 b in the secondlayer on the transfer branching position X, is connected by the contact17 a to the metal wiring 11.

Further, an electric field directing area 19 is implanted below thetransfer gates 15 a and 15 b in the second layer.

FIG. 2( b) illustrates a plan view pattern of the transfer gates 14 aand 14 b in the first layer in the first horizontal CCD section 103 a.FIG. 2( c) illustrates a plan view pattern of the transfer gates 14 aand 14 b in the first layer in the second horizontal CCD section 103 bdescribed above. Thus, the solid-state image capturing apparatusaccording to the embodiment is configured by changing the plan viewpattern of the φH1 wiring 10 (metal wiring) and the φH2 wiring 11 (metalwiring) from the conventional pattern and forming the transfer branchingposition X. That is, a mask pattern of the metal wiring layer is changedfor one layer.

Therefore, in the first CCD section 103 a for performing the transfer inthe left direction to the output section on the left end, thearrangement order for the contacts, which connect the transfer gates 14a and 14 b in the first layer and the transfer gates 15 a and 15 b inthe second layer to the metal wirings 10 and 11, is arranged in theorder of the positions of the transfer gates from the left side of FIG.2. That is, the order is arranged with the contact 17 a connecting the(φH2 wiring 11 and the transfer gate 14 b in the first layer, thecontact 17 b connecting the φH2 wiring 11 and the transfer gate 15 b inthe second layer, the contact 16 a connecting the 15 b H1 wiring 10 andthe transfer gate 14 a in the first layer, the contact 16 b connectingthe φH1 wiring 10 and the transfer gate 15 a in the second layer, thecontact 17 a connecting the φH2 wiring 11 and the transfer gate 14 b inthe first layer . . . from the left side of FIG. 2. With such aconnection, the electric charges in the horizontal transfer section aretransferred by the transfer pulse φH1 and the transfer pulse φH2described above in the left direction where the output section 4 islocated.

On the other hand, in the second CCD section 103 b positioned on theright side of the transfer branching position X, the arrangement orderfor the contacts, which connect the transfer gates 14 a and 14 b in thefirst layer and the transfer gates 15 a and 15 b in the second layer tothe metal wirings 10 and 11, is arranged in the order of the positionsof the transfer gates. That is, the arrangement order begins with thecontact 17 b connecting the φH2 wiring 11 and the transfer gate 15 b inthe second layer, the contact 17 a connecting the φH2 wiring 11 and thetransfer gate 14 b in the first layer, the contact 16 b connecting the(φH1 wiring 10 and the transfer gate 15 a in the first layer, thecontact 16 a connecting the φH1 wiring 10 and the transfer gate 14 a inthe first layer, the contact 17 b connecting the φH2 wiring 11 and thetransfer gate 15 b in the second layer . . . from the left side of FIG.2. With such a connection, the electric charges in the second CCDsection 103 b are transferred in the left direction opposite from theoutput section 4 (in the right direction in the figure).

Next, an operation will be described.

In the solid-state image capturing apparatus 100 according to Embodiment1, the area used for image capturing in the effective pixel area isdefined as the pixel cutting out area 25. Therefore, the transferbranching position X in the horizontal transfer section 103 is set inthe position corresponding to the right end of the pixel cutting outarea 25.

In the solid-state image capturing apparatus 100 according to Embodiment1, electric charges generated in each pixel section are transferred inthe vertical direction by the vertical transfer section 2. When theelectric charges are sent to the horizontal transfer section 103 foreach pixel row by the transfer in the vertical direction, the horizontaltransfer section 103 transfers the electric charges in the horizontaldirection for each pixel row.

At this stage, in the horizontal transfer section 103, electric chargesin the CCD section 103 a on the left side of the transfer branchingposition X are transferred to the output section 4 and electric chargesin the CCD section 103 b on the right side of the transfer branchingposition X are transferred to a longitudinal edge section of thehorizontal sweeping drain 106, both by the two-phase driving pulses φH1and φH2 to the transfer gates.

That is, in the CCD section 103 a on the left side of the horizontaltransfer gate 103, the first driving pulse φH1 is applied to thetransfer gate 15 a in the second layer positioned on the electric fielddirecting area 19 and to the transfer gate 14 a in the first layer onthe left side of the transfer gate 15 a, and the second driving pulseφH2 is applied to the transfer gate 15 b in the second layer positionedon the electric field directing area 19 and to the transfer gate 14 b inthe first layer on the left side of the transfer gate 15 b.Subsequently, when the driving pulse φH1 is in a high level, thepotential level becomes deeper in the lower side of the transfer gate 14a in the first layer than the lower side of the transfer gate 15 a inthe second layer. Electric charges will always move to the left side inthe transfer areas associated with these transfer gates. In addition,when the driving pulse φH2 is in a high level, the potential levelbecomes deeper in the lower side of the transfer gate 14 b in the firstlayer than the lower side of the transfer gate 15 b in the second layer.Electric charges will always move to the left side in the transfer areasassociated with these transfer gates. As a result, electric charges inthe CCD section 103 a on the left side of the horizontal transfersection 103 are transferred to the output section 4 side by thealternate change of the driving pulses φH1 and φH2 described above inhigh and low levels, as illustrated in FIG. 4.

On the other hand, in the CCD section 103 b on the right side of thehorizontal transfer gate 103, the first driving pulse φH1 is applied tothe transfer gate 15 a in the second layer positioned on the electricfield directing area 19 and to the transfer gate 14 a in the first layeron the right side of the transfer gate 15 a, and the second drivingpulse φH2 is applied to the transfer gate 15 b in the second layerpositioned on the electric field directing area 19 and to the transfergate 14 b in the first layer on the right side of the transfer gate 15b. Subsequently, when the driving pulse φH1 is in a high level, thepotential level becomes deeper in the lower side of the transfer gate 14a in the first layer than the lower side of the transfer gate 15 a inthe second layer. Electric charges will always move to the right side inthe transfer areas associated with these transfer gates. In addition,when the driving pulse φH2 is in a high level, the potential levelbecomes deeper in the lower side of the transfer gate 14 b in the firstlayer than the lower side of the transfer gate 15 b in the second layer.Electric charges will always move to the right side in the transferareas associated with these transfer gates. As a result, electriccharges in the CCD section 103 b on the right side of the horizontaltransfer section 103 are transferred to the longitudinal edge section ofthe horizontal sweeping drain by the alternate change of the drivingpulses φH1 and φH2 described above in high and low levels, asillustrated in FIG. 4.

The number of horizontal steps among the number of the total effectivepixels is defined as N, and the number of horizontal transfer steps fromthe left end of the pixel row to the transfer branching position X, thatis the number of transfer electrodes configured with a pair of adjacenttransfer gates (transfer gate in the first layer and the transfer gatein the second layer), is defined as M. At this stage, the transferperiod of one horizontal line is complete in the clock of M time(s), andthe number of horizontal steps N among the number of the total effectivepixels>the number of horizontal transfer steps M to the transferbranching position (the minimum value of M=N/2) holds. Therefore, thehorizontal transfer period can be significantly shortened. Further, aprocess for sweeping out unnecessary electric charges can be performedat the same time.

According to Embodiment 1 with the configuration described above, in thesolid-state image capturing apparatus 100 including the plurality ofpixel sections 1 arranged in a two dimensional array for performingphotoelectric conversions on incident light to generate electriccharges; the vertical transfer section 2 positioned in association witheach pixel column for transferring the electric charges read out frompixels of each pixel column in the vertical direction; the horizontaltransfer section 103 for transferring the electric charges transferredfrom the vertical transfer section in the horizontal direction, thelayout pattern is set such that the φH1 wiring 10 and the φH2 wiring 11in the horizontal transfer section 103 are connected to correspondingtransfer gates so that these wirings have opposing electric chargetransferring directions on both sides of the predetermined transferbranching position X of the horizontal transfer section. Therefore, inthe horizontal CCD (horizontal transfer section), the transfer branchingposition for the area transferring electric charges as necessaryelectric charges in a predetermined direction and the area for sweepingout electric charges in a reverse direction as unnecessary electriccharges, can be arbitrarily set by the layout pattern for members toconstitute the horizontal transfer section. Thus, necessary electriccharges can be effectively transferred by the driving of the horizontaltransfer section. As a result, the driving frequency of the horizontalCCD can be reduced at the time of reading out the necessary electriccharges from a partial area of the effective pixel area without addinganother circuit configuration for sweeping out unnecessary electriccharges.

Embodiment 2

FIG. 5 is a diagram illustrating a solid-state image capturing apparatusaccording to Embodiment 2 of the present invention, illustrating alayout of a transfer gate and a wiring in its horizontal transfersection (FIG. 5( a)) and a plan view form of a transfer gate in a firstlayer (FIGS. 5( b) and 5(c)).

Similar to the solid-state image capturing apparatus according toEmbodiment 1, the solid-state image capturing apparatus according toEmbodiment 2 includes: a plurality of pixel sections positioned in amatrix for photoelectrically converting an incident light into a signalcharge; a vertical transfer section for reading out the signal chargestored in each of the pixel sections to transfer it in a columndirection (vertical direction); a horizontal transfer section fortransferring the signal charge from the vertical transfer section in arow direction (horizontal direction); and an output section foramplifying the transferred signal charge and outputting it as an imagecapturing signal. The solid-state image capturing apparatus according toEmbodiment 2 includes a different plan view pattern of a transfer gate,a φH1 wiring and a φH2 wiring in the horizontal transfer section fromthe pattern of the solid-state image capturing apparatus according toEmbodiment 1. However, these patterns are the same in the left and rightportions of the transfer branching position in the horizontal transfersection. According to Embodiment 2, the arrangement pattern of a contactthat connects the transfer gate and the wiring is different in the leftand right portions of the transfer branching position. Since otherconfigurations of Embodiment 2 are the same as those of Embodiment 1described above, a connecting configuration of the transfer gate and thewiring in the horizontal transfer section will be described hereinafter.

As illustrated in FIG. 5( a), the horizontal transfer section 203 isarranged therein with a plurality of transfer gates 24 a, 24 b, 25 a and25 b consecutively and repetitively in the horizontal transfer directionfor transferring electric charges transferred from the vertical transfersection 2 in the horizontal direction.

Herein, the transfer gates 24 a and 24 b are transfer gates in the firstlayer, the transfer gates being formed by placing a first polysiliconfilm using a mask pattern. Further, the transfer gates 25 a and 25 b aretransfer gates in the second layer, the transfer gates being formed byplacing a second polysilicon film positioned above the first polysiliconfilm using a mask pattern.

In addition, a first driving pulse φH1 is applied to the transfer gates24 a and 25 a, and a second driving pulse φH2 is applied to the transfergates 24 b and 25 b. That is, according to Embodiment 2 of the presentinvention, the horizontal transfer section 203 is configured to transfersignal charges of one packet by two-phase gates, to which the first andsecond driving pulses φH1 and φH2 are applied.

In detail, the transfer gate 25 b in the second layer is positioned in atransfer branching position X of the horizontal transfer section 203. Inaddition, the transfer gate 25 a in the second layer, the transfer gate24 a in the first layer, the transfer gate 25 b in the second layer, andthe transfer gate 24 b in the first layer are repetitively arranged in afirst horizontal CCD section 203 a positioned on one side of thetransfer branching position X, for transferring electric charges to theoutput section 4, in this order towards the direction to which electriccharges are transferred (left direction in the figure). Further, thetransfer gate 25 a in the second layer, the transfer gate 24 a in thefirst layer, the transfer gate 25 b in the second layer, and thetransfer gate 24 b in the first layer are repetitively arranged in asecond horizontal CCD section 203 b positioned on the other side of thetransfer branching position X for transferring electric charges towardsthe sweeping drain 106, in this order towards the direction to whichelectric charges are transferred (right direction in the figure).

Further, in an electric charge transfer area 203 c for transferringelectric charges below the transfer gates 25 a and 25 b in the secondlayer, a diffusion area 19 (see FIG. 4) is formed for orienting anelectric field so that a transferring direction is determined fortransferring electric charges when the driving pulse described above isapplied. Note that the cross section along VA-VA′ in FIG. 5 is the sameas the cross sectional structure along IIA-IIA′ in FIG. 2 illustrated inFIG. 4.

On the end of one side of the transfer gates, wirings 20 and 21 arepositioned for supplying a two-phase driving pulse of each of thetransfer gates described above. The wirings are formed by placing metalfilms formed in a pattern with an insulation film interposed above apolysilicon film forming the transfer gates described above. The wiringsare connected to each of the transfer gates through a contact hole thatpenetrates the insulation film.

That is, in the first horizontal CCD section 203 a on the one side (leftside in the figure) of the transfer branching position X, the transfergate 25 a in the second layer and the transfer gate 24 a in the firstlayer positioned on the left side and adjacent to the transfer gate 25 aare connected respectively via contacts 16 a and 16 b to the metalwiring 20 that supplies the first driving pulse φH1, and the transfergate 25 b in the second layer and the transfer gate 24 b positioned onthe left side and adjacent to the transfer gate 25 b are connectedrespectively via contacts 17 a and 17 b to the metal wiring 21 thatsupplies the second driving pulse φH2. As a result, in the firsthorizontal CCD 203 a, the transfer gate 25 a in the second layer and thetransfer gate 24 a in the first layer positioned on the left side form aφH1 transferring electrode 22, and the transfer gate 25 b in the secondlayer and the transfer gate 24 b positioned on the left side form a φH2transferring electrode 23.

On the other hand, in the second horizontal CCD section 203 b on theother side (right side in the figure) of the transfer branching positionX, the transfer gate 25 a in the second layer and the transfer gate 24 ain the first layer positioned on the right side and adjacent to thetransfer gate 25 a are connected respectively via contacts 26 a and 26 bto the metal wiring 20 that supplies the first driving pulse φH1, andthe transfer gate 25 b in the second layer and the transfer gate 24 bpositioned on the right side and adjacent to the transfer gate 25 b areconnected respectively via contacts 27 a and 27 b to the metal wiring 21that supplies the second driving pulse φH2. As a result, in the secondhorizontal CCD 203 b, the transfer gate 25 a in the second layer and thetransfer gate 24 a in the first layer positioned on the right side forma φH1 transferring electrode 22, and the transfer gate 25 b in thesecond layer and the transfer gate 24 b positioned on the left side forma φH2 transferring electrode 23.

In addition, in the transfer branching position X, the transfer gate 25b in the second layer positioned on the transfer branching position X isconnected by the contact 17 b to the metal wiring 11 that supplies thesecond driving pulse φH2. The transfer gate 24 b, which is positioned onthe left side of the transfer gate 25 b positioned on the transferbranching position X, is connected by the contact 27 a to the metalwiring 21. The transfer gate 24 b, which is in the first layerpositioned on the right side of the transfer gate 25 b in the secondlayer on the transfer branching position X, is connected by the contact27 a to the metal wiring 21.

FIG. 5( b) illustrates plan view patterns of the transfer gates 24 a and24 b in the first layer in the first horizontal CCD section 203 a, andFIG. 5( c) illustrates plan view patterns of the transfer gates 24 a and24 b in the first layer in the second horizontal CCD section 203 b. Theplan view patterns of these transfer gates are the same in thisembodiment.

Thus, the solid-state image capturing apparatus according to Embodiment2 has a layout pattern of the contact connecting the transfer gate andthe wiring, the layout pattern being different in the left and rightportions of the transfer branching position in the horizontal transfersection such that corresponding transfer gates are connected to the φH1wiring and the (φH2 wiring so that electric charge transferringdirections will be opposite on both sides of the predetermined transferbranching position X of the horizontal transfer section.

Next, an operation will be described.

In the solid-state image capturing apparatus according to Embodiment 2,as well, electric charges generated in each pixel section aretransferred in the vertical direction by the vertical transfer section2. When the electric charges are sent to the horizontal transfer section203 for each pixel row by this vertical transferring, the horizontaltransfer section 203 transfers the electric charges for each pixel rowin the horizontal direction.

At this stage, in the horizontal transfer section 203, electric chargesin the CCD section 203 a on the left side of the transfer branchingposition X are transferred to the output section and electric charges inthe CCD section 203 b on the right side of the transfer branchingposition X are transferred to a longitudinal end section side of thehorizontal sweeping drain, both by the two-phase driving pulses φH1 andφH2 to the transfer gates.

That is, in the CCD section 203 a on the left side of the horizontaltransfer gate 203, the first driving pulse φH1 is applied to thetransfer gate 25 a in the second layer positioned on the electric fielddirecting area and to the transfer gate 24 a in the first layer on theleft side of the transfer gate 25 a, and the second driving pulse φH2 isapplied to the transfer gate 25 b in the second layer positioned on theelectric field directing area and to the transfer gate 24 b in the firstlayer on the left side of the transfer gate 25 b. Subsequently, electriccharges move to the left side, as similar to Embodiment 1.

On the other hand, in the CCD section 203 b on the right side of thehorizontal transfer gate 203, the first driving pulse φH1 is applied tothe transfer gate 25 a in the second layer positioned on the electricfield directing area and to the transfer gate 24 a in the first layer onthe right side of the transfer gate 25 a, and the second driving pulseφH2 is applied to the transfer gate 25 b in the second layer positionedon the electric field directing area and to the transfer gate 24 b inthe first layer on the right side of the transfer gate 25 b.Subsequently, electric charges move to the right side, and the electriccharges are transferred to the longitudinal end section of thehorizontal sweeping drain, as similar to Embodiment 1.

According to Embodiment with the configuration described above, in thesolid-state image capturing apparatus including the plurality of pixelsections 1 arranged in a two dimensional array for performingphotoelectric conversions on incident light to generate electriccharges; the vertical transfer section 2 positioned associating witheach pixel column for transferring the electric charges read out frompixels of each pixel column in the vertical direction; the horizontaltransfer section 203 for transferring the electric charges transferredfrom the vertical transfer section in the horizontal direction, thelayout pattern of the contact connecting the transfer gate and thewiring is changed such that corresponding transfer gates are connectedto the φH1 wiring 20 and the φH2 wiring 21 so that electric chargetransferring directions become opposite on both sides of thepredetermined transfer branching position X of the horizontal transfersection. Therefore, in the horizontal CCD (horizontal transfer section),the transfer branching position for the area transferring electriccharges as necessary electric charges in a predetermined direction andthe area for sweeping out electric charges in a reverse direction asunnecessary electric charges, can be arbitrarily set by the layoutpattern of the contact. Thus, necessary electric charges can beeffectively transferred by the driving of the horizontal transfersection. As a result, the driving frequency of the horizontal CCD can bereduced at the time of reading out the necessary electric charges from apartial area of the effective pixel area without adding another circuitconfiguration for sweeping out unnecessary electric charges.

Embodiment 3

FIGS. 6 and 7 are diagrams illustrating a solid-state image capturingapparatus according to Embodiment 3 of the present invention. FIG. 6illustrates a layout of a transfer gate and a wiring in a horizontaltransfer section. FIG. 7 illustrates a plan view form of a transfer gatein a first layer (FIGS. 7( a), 7(b)), and a plan view form of a transfergate in a second layer (FIG. 7( c)).

According to the solid-state image capturing apparatus of Embodiment 3,the layout pattern of the transfer gate is set such that correspondingtransfer gates are connected to the φH1 wiring 30 and the φH2 wiring 31so that electric charge transferring directions become opposite on bothsides of the predetermined transfer branching position X of thehorizontal transfer section. That is, in Embodiment 3, the layoutpattern of the transfer gate, instead of the layout pattern of thewiring in Embodiment 1 or the layout pattern of the contact inEmbodiment 2, is set to be different in the left and right portions ofthe transfer branching position in the horizontal transfer section.Except for this point, the configuration is the same as those of theother embodiments described above.

As illustrated in FIG. 6, the horizontal transfer section 303 of thesolid-state image capturing apparatus according to Embodiment 3 isarranged therein with a plurality of transfer gates 34 a, 34 b, 35 a and35 b consecutively and repetitively in the horizontal transfer directionfor transferring electric charges transferred from the vertical transfersection 2 in the horizontal direction.

Herein, the transfer gates 34 a and 34 b are transfer gates in the firstlayer, the transfer gates being formed by placing a first polysiliconfilm using a mask pattern. Further, the transfer gates 35 a and 35 b aretransfer gates in the second layer, the transfer gates being formed byplacing a second polysilicon film positioned above the first polysiliconfilm using a mask pattern.

In addition, a first driving pulse φH1 is applied to the transfer gates34 a and 35 a, and a second driving pulse φH2 is applied to the transfergates 34 b and 35 b. That is, according to Embodiment 3 of the presentinvention, the horizontal transfer section 303 is configured to transfersignal charges of one packet by two-phase gates, to which the first andsecond driving pulses φH1 and φH2 are applied.

In detail, the transfer gate 35 b in the second layer is positioned in atransfer branching position X of the horizontal transfer section 303. Inaddition, the transfer gate 35 a in the second layer, the transfer gate34 a in the first layer, the transfer gate 35 b in the second layer, andthe transfer gate 34 b in the first layer are repetitively arranged in afirst horizontal CCD section 303 a positioned on one side of thetransfer branching position X, for transferring electric charges to theoutput section, in this order towards the direction to which electriccharges are transferred (left direction in the figure). Further, thetransfer gate 35 a in the second layer, the transfer gate 34 a in thefirst layer, the transfer gate 35 b in the second layer, and thetransfer gate 34 b in the first layer are repetitively arranged in thesecond horizontal CCD section 203 b positioned on the other side of thetransfer branching position X for transferring electric charges towardsthe sweeping drain, in this order towards the direction to whichelectric charges are transferred (right direction in the figure).

Further, in an electric charge transfer area for transferring electriccharges below the transfer gates 35 a and 35 b in the second layer, adiffusion area (see FIG. 4) is formed for orienting an electric field sothat a transferring direction is determined for transferring electriccharges when the driving pulse described above is applied. Note that thecross section along VIA-VIA′ in FIG. 6 is the same as thecross-sectional structure along IIA-IIA′ in FIG. 2 illustrated in FIG.4.

On the end of one side of the transfer gates, wirings 30 and 31 arepositioned for supplying a two-phase driving pulse of each of thetransfer gates described above. The wirings are formed by placing metalfilms formed in a pattern with an insulation film interposed above apolysilicon film forming the transfer gates described above. The wiringsare connected to each of the transfer gates through a contact hole thatpenetrates the insulation film.

That is, in the first horizontal CCD section 303 a on the one side (leftside in the figure) of the transfer branching position X, the transfergate 35 a in the second layer and the transfer gate 34 a in the firstlayer positioned on the left side and adjacent to the transfer gate 35 aare connected respectively via contacts 36 a and 36 b to the metalwiring 30 that supplies the first driving pulse φH1, and the transfergate 35 b in the second layer and the transfer gate 34 b positioned onthe left side and adjacent to the transfer gate 35 b are connectedrespectively via contacts 37 a and 37 b to the metal wiring 21 thatsupplies the second driving pulse φH2. As a result, in the firsthorizontal CCD 303 a, the transfer gate 35 a in the second layer and thetransfer gate 34 a in the first layer positioned on the left side form aφH1 transferring electrode 32, and the transfer gate 35 b in the secondlayer and the transfer gate 34 b positioned on the left side form a φH2transferring electrode 33.

On the other hand, in a second horizontal CCD section 303 b on the otherside (right side in the figure) of the transfer branching position X,the transfer gate 35 a in the second layer and the transfer gate 34 a inthe first layer positioned on the right side and adjacent to thetransfer gate 35 a are connected respectively via contacts 36 a and 36 bto the metal wiring 30 that supplies the first driving pulse φH1, andthe transfer gate 35 b in the second layer and the transfer gate 34 bpositioned on the right side and adjacent to the transfer gate 35 b areconnected respectively via contacts 37 a and 37 b to the metal wiring 31that supplies the second driving pulse φH2. As a result, in the secondhorizontal CCD 303 b, the transfer gate 35 a in the second layer and thetransfer gate 34 a in the first layer positioned on the right side forma φH1 transferring electrode 32, and the transfer gate 35 b in thesecond layer and the transfer gate 34 b positioned on the left side forma φH2 transferring electrode 33.

In addition, in the transfer branching position X, the transfer gate 35b in the second layer positioned on the transfer branching position X isconnected by the contact 37 b to the metal wiring 11 that supplies thesecond driving pulse φH2. The transfer gate 34 b, which is positioned onthe left side of the transfer gate 35 b positioned on the transferbranching position X, is connected by the contact 37 a to the metalwiring 31. The transfer gate 34 b, which is in the first layerpositioned on the right side of the transfer gate 35 b in the secondlayer on the transfer branching position X, is connected by the contact37 a to the metal wiring 31.

Further, an electric field directing area is implanted below thetransfer gates 35 a and 35 b in the second layer.

Thus, according to the solid-state image capturing apparatus ofEmbodiment 3, the plan view patterns of the transfer gates 34 a and 34 bin the first layer and the plan view patterns of the transfer gates 35 aand 35 b in the second layer have been changed from those of Embodiment1 to form the transfer branching position. The plan view patterns of thetransfer gates 35 a and 35 b in the second layer are set to be the sameon both side portions of the transfer branching position X and the planview patterns of the transfer gates 34 a and 34 b in the first layer areset to be different on both side portions of the transfer branchingposition X.

Next, an operation will be described.

In the solid-state image capturing apparatus according to Embodiment 3,as well, electric charges generated in each pixel section aretransferred in the vertical direction by the vertical transfer section2. When the electric charges are sent to the horizontal transfer section303 for each pixel row by this vertical transferring, the horizontaltransfer section 303 transfers the electric charges for each pixel rowin the horizontal direction.

At this stage, in the horizontal transfer section 303, electric chargesin the CCD section 303 a on the left side of the transfer branchingposition X are transferred to the output section and electric charges inthe CCD section 303 b on the right side of the transfer branchingposition X are transferred to a longitudinal end section side of thehorizontal sweeping drain, both by the two-phase driving pulses φH1 andφH2 to the transfer gates.

That is, in the CCD section 303 a on the left side of the horizontaltransfer gate 303, the first driving pulse φH1 is applied to thetransfer gate 35 a in the second layer positioned on the electric fielddirecting area and to the transfer gate 34 a in the first layer on theleft side of the transfer gate 35 a, and the second driving pulse φH2 isapplied to the transfer gate 35 b in the second layer positioned on theelectric field directing area and to the transfer gate 34 b in the firstlayer on the left side of the transfer gate 35 b. Subsequently, electriccharges move to the left side, as similar to Embodiment 1.

On the other hand, in the CCD section 303 b on the right side of thehorizontal transfer gate 303, the first driving pulse φH1 is applied tothe transfer gate 35 a in the second layer positioned on the electricfield directing area and to the transfer gate 34 a in the first layer onthe right side of the transfer gate 35 a, and the second driving pulseφH2 is applied to the transfer gate 35 b in the second layer positionedon the electric field directing area and to the transfer gate 34 b inthe first layer on the right side of the transfer gate 35 b.Subsequently, electric charges move to the right side, and the electriccharges are transferred to the longitudinal end section of thehorizontal sweeping drain, as similar to Embodiment 1.

According to Embodiment with the configuration described above, in thesolid-state image capturing apparatus including the plurality of pixelsections 1 arranged in a two dimensional array for performingphotoelectric conversions on incident light to generate electriccharges; the vertical transfer section 2 positioned associating witheach pixel column for transferring the electric charges read out frompixels of each pixel column in the vertical direction; the horizontaltransfer section 303 for transferring the electric charges transferredfrom the vertical transfer section in the horizontal direction, thelayout pattern of the corresponding transfer gate is set such thatcorresponding transfer gates are connected to the φH1 wiring 30 and theφH2 wiring 31 so that electric charge transferring directions becomeopposite on both sides of the predetermined transfer branching positionX of the horizontal transfer section. Therefore, in the horizontal CCD(horizontal transfer section), the transfer branching position for thearea transferring electric charges as necessary electric charges in apredetermined direction and the area for sweeping out electric chargesin a reverse direction as unnecessary electric charges, can bearbitrarily set by the layout pattern of the transfer gate. Thus,necessary electric charges can be effectively transferred by the drivingof the horizontal transfer section. As a result, the driving frequencyof the horizontal CCD can be reduced at the time of reading out thenecessary electric charges from a partial area of the effective pixelarea without adding another circuit configuration for sweeping outunnecessary electric charges.

In each of the embodiments described above, the φH1 wiring and the φH2wiring are formed with the pattern of the same metal wiring layer.However, these wirings may be formed with the pattern of different metallayers.

Further, in each of the embodiments described above, the driving signalapplied to the transfer gate is a two-phase driving signal. However, thehorizontal transfer section may be driven by a driving signal of threephases or more.

Further, in each of the embodiments described above, the solid-stateimage capturing apparatus is illustrated as including the output sectionpositioned only on one side of the horizontal transfer section. However,in the solid-state image capturing apparatus, the output section may bepositioned on both sides of the horizontal transfer section andnecessary electric charges may be transferred separately by each outputsection, so that the transfer efficiency can be increased. In this case,the electric charges processed in each output section are necessaryelectric charges, and in image data can be made by processing theoutputs of both output sections together in a signal processing circuitin the later step.

In addition, in the embodiments described above, the transfer branchingposition X is set to be in the middle portion of the horizontal transfersection. However, the transfer branching position X may be set on theend of one side or the other end side of the horizontal transfer sectionby changing the layout pattern of the horizontal transfer section.

Further, in the embodiments described above, the layout pattern of thetransfer gate or the layout pattern of the signal wiring is set suchthat the transfer gate and the signal wiring are connected to each otherso that the electric charge transferring directions will be oppositefrom each other on both sides of the transfer branching position in thehorizontal transfer section. However, the layout pattern of the contactlayer connecting the transfer gate and the signal wiring may be set suchthat the transfer gate and the signal wiring are connected to each otherso that the electric charge transferring directions will be oppositefrom each other on both sides of the transfer branching position in thehorizontal transfer section. That is, any layer may be changed as longas the layout pattern of one or more layers on the members to constitutethe horizontal transfer section is changed so that the electric chargetransferring directions will be opposite from each other on both sidesof the transfer branching position in the horizontal transfer section.

Embodiment 4

Although not specifically described in Embodiments 1 to 3 describedabove, an electronic information device having an image input devicewill be described, the electric information device, such as a digitalcamera (e.g., digital video camera and digital still camera), an imageinput camera, a scanner, a facsimile machine and a camera-equipped cellphone device, using at least any of the solid-state image capturingapparatuses according to Embodiments 1 to 3 described above in an imagecapturing section.

FIG. 8 is a block diagram illustrating an exemplary diagrammaticstructure of an electronic information device, as Embodiment 4 of thepresent invention, using the solid-state image capturing apparatusaccording to any of Embodiments 1 to 3 of the present invention as animage input device in an image capturing section.

The electronic information device 90 according to Embodiment 4 of thepresent invention as illustrated in FIG. 8 includes any of thesolid-state image capturing apparatuses according to Embodiment 1 to 3of the present invention as an image capturing section 91 for capturinga subject. The electronic information device 90 further includes atleast any of: a memory section 92 (e.g., recording media) fordata-recording a high-quality image data obtained by using at least anyof the solid-state image capturing apparatuses according to Embodiments1 to 3 in an image capturing section, after a predetermined signalprocess is performed on the image data for recording; a display section93 (e.g., liquid crystal display device) for displaying this image dataon a display screen (e.g., liquid crystal display screen) after apredetermined signal process is performed for display; a communicationsection 94 (e.g., transmitting and receiving device) for communicatingthis image data after a predetermined signal process is performed on theimage data for communication; and an image output section 95 forprinting (typing out) and outputting (printing out) this image data.

As described above, the present invention is exemplified by the use ofits preferred embodiments. However, the present invention should not beinterpreted solely based on the embodiments described above. It isunderstood that the scope of the present invention should be interpretedsolely based on the claims. It is also understood that those skilled inthe art can implement equivalent scope of technology, based on thedescription of the present invention and common knowledge from thedescription of the detailed preferred embodiments of the presentinvention. Furthermore, it is understood that any patent, any patentapplication and any references cited in the present specification shouldbe incorporated by reference in the present specification in the samemanner as the contents are specifically described therein.

INDUSTRIAL APPLICABILITY

The present invention can be applied in the field of a solid-state imagecapturing apparatus; a driving method of the solid-state image capturingapparatus; and an electronic information device using the solid-stateimage capturing apparatus. According to the present invention, atransfer branching position for an area for transferring electriccharges as necessary electric charges in a predetermined direction andan area for transferring electric charges in a reverse direction, can bearbitrarily set inside the horizontal transfer section in thesolid-state image capturing apparatus by the layout pattern for themembers to constitute the horizontal transfer section. As a result,necessary electric charges can be effectively transferred by the drivingof the horizontal transfer section, and further, the driving frequencyof the horizontal CCD can be reduced at the time of reading out thenecessary electric charges from a partial area of the effective pixelarea without adding another circuit configuration for sweeping outunnecessary electric charges.

Various other modifications will be apparent to and can be readily madeby those skilled in the art without departing from the scope and spiritof this invention. Accordingly, it is not intended that the scope of theclaims appended hereto be limited to the description as set forthherein, but rather that the claims be broadly construed.

1. A solid-state image capturing apparatus comprising: a plurality ofpixel sections positioned in an array for photoelectrically convertingan incident light into a signal charge; a vertical transfer section fortransferring the signal charge read out from each of the pixel sectionsin a vertical direction; and a horizontal transfer section fortransferring the signal charge transferred from the vertical transfersection in a horizontal direction, wherein the horizontal transfersection includes a plurality of transfer gates consecutively arranged ina horizontal direction, and a signal wiring for supplying a drivingsignal to the transfer gates, wherein a layout pattern of at least onelayer of constituent members constituting the horizontal transfersection is a pattern in which the transfer gates and the signal wiringare connected so that electric charge transfer directions becomeopposite from each other on both sides of a branching position in thehorizontal transfer section.
 2. A solid-state image capturing apparatusaccording to claim 1, wherein the horizontal transfer section includes:a first transfer electrode configured of two adjacent transfer gates anddriven by a first driving signal; a second transfer electrode formed oftwo adjacent transfer gates and driven by a second driving signal, whichhas a reversed phase from the first driving signal; a first signalwiring for supplying the first driving signal to the transfer gates thatconfigure the first transfer electrode; and a second signal wiring forsupplying the second driving signal to the transfer gates that configurethe first transfer electrode.
 3. A solid-state image capturing apparatusaccording to claim 2, wherein the first signal wiring and the secondsignal wiring are formed by patterning a same metal layer.
 4. Asolid-state image capturing apparatus according to claim 2, wherein thefirst signal wiring is formed by patterning a first metal layer, andwherein the second signal wiring is formed by patterning a second metallayer, which is different from the first metal layer.
 5. A solid-stateimage capturing apparatus according to claim 2, wherein a layout patternof the first and second signal wirings is a pattern in which thetransfer gates and the signal wiring are connected so that electriccharge transferring directions are opposite from each other on bothsides of a predetermined position in the horizontal transfer section. 6.A solid-state image capturing apparatus according to claim 5, whereinone of the two adjacent transfer gates that configure the first transferelectrode is formed by patterning a first polysilicon layer, and theother of the two adjacent transfer gates is formed by patterning asecond polysilicon layer different from the first polysilicon layer, andwherein one of the two adjacent transfer gates that configure the secondtransfer electrode is formed by patterning the first polysilicon layer,and the other of the two adjacent transfer gates is formed by patterningthe second polysilicon layer.
 7. A solid-state image capturing apparatusaccording to claim 6, wherein the four transfer gates that configure theadjacent first and second transfer electrodes are first to fourthtransfer gates consecutively arranged in a horizontal direction, and thefirst to fourth transfer gates have different plan view forms.
 8. Asolid-state image capturing apparatus according to claim 7, wherein, onone side of a predetermined position in the horizontal transfer section,the first transfer electrode is configured of the first and secondtransfer gates and the second transfer electrode is configured of thethird and fourth transfer gates; and wherein, on the other side of apredetermined position in the horizontal transfer section, the firsttransfer electrode is configured of the second and third transfer gatesand the second transfer electrode is configured of the fourth and firsttransfer gates.
 9. A solid-state image capturing apparatus according toclaim 2, wherein a layout pattern of a plurality of transfer gates thatconfigure the first and second transfer electrodes is a pattern in whichthe transfer gates and the signal wiring are connected so that electriccharge transferring directions become opposite from each other on bothsides of a predetermined position in the horizontal transfer section.10. A solid-state image capturing apparatus according to claim 9,wherein one of the two adjacent transfer gates that configure the firsttransfer electrode is formed by patterning a first polysilicon layer,and the other of the two adjacent transfer gates is formed by patterninga second polysilicon layer different from the first polysilicon layer,and wherein one of the two adjacent transfer gates that configure thesecond transfer electrode is formed by patterning the first polysiliconlayer, and the other of the two adjacent transfer gates is formed bypatterning the second polysilicon layer.
 11. A solid-state imagecapturing apparatus according to claim 10, wherein the four transfergates that configure the adjacent first and second transfer electrodesare first to fourth transfer gates consecutively arranged in ahorizontal direction, the first transfer gate and the third transfergate having the same plan view form, and the second transfer gate andthe fourth transfer gate having the same plan view form.
 12. Asolid-state image capturing apparatus according to claim 11, wherein, onone side of a predetermined position in the horizontal transfer section,the first transfer electrode is configured of the first and secondtransfer gates and the second transfer electrode is configured of thethird and fourth transfer gates; and wherein, on the other side of apredetermined position in the horizontal transfer section, the firsttransfer electrode is configured of the second and third transfer gatesand the second transfer electrode is configured of the fourth and firsttransfer gates.
 13. A solid-state image capturing apparatus according toclaim 1, further including an output section positioned on either of oneend side or the other end side of the horizontal transfer section, foroutputting a signal charge from the horizontal transfer section as animage capturing signal, wherein the horizontal transfer sectiontransfers unnecessary electric charges from the vertical transfersection in an opposite direction of the output section from thebranching position.
 14. A solid-state image capturing apparatusaccording to claim 1, further including: a first output sectionpositioned on one end side of the horizontal transfer section foroutputting a signal charge from the horizontal transfer section as animage capturing signal; and a second output section positioned on theother end side of the horizontal transfer section for outputting asignal charge from the horizontal transfer section as an image capturingsignal.
 15. A solid-state image capturing apparatus according to claim1, wherein the branching position is set at an arbitrary position in thehorizontal transfer section by changing one or more layers of a layoutpattern of constituent members that constitute the horizontal transfersection.
 16. A solid-state image capturing apparatus according to claim15, wherein mask patterns other than mask patterns corresponding to thechanged layout pattern are shared among solid-state image capturingapparatuses having the different branching positions.
 17. A solid-stateimage capturing apparatus according to claim 1, further including ahorizontal drain positioned on the opposite side of the output sectionof the horizontal transfer section, for sweeping out the unnecessaryelectric charges.
 18. A solid-state image capturing apparatus accordingto claim 1, wherein the horizontal transfer section is configured to setthe predetermined position by the layout pattern for the constituentmembers which constitute the horizontal transfer section, so that pixelsections with fewer than the number of the effective pixels, which isthe number of the plurality of pixel sections positioned in an array, isused as pixel sections that constitute an image capturing area.
 19. Asolid-state image capturing apparatus according to claim 1, wherein alayout pattern of the constituent members, which constitute thehorizontal transfer section, is any of a layout pattern of the transfergates, a layout pattern of the signal wiring, and a layout pattern of acontact layer connecting the transfer gates and the signal wiring.
 20. Asolid-state image capturing apparatus according to claim 1, wherein thehorizontal transfer section drives the transfer gates by a drivingsignal of three phases or more.
 21. A driving method for driving thesolid-state image capturing apparatus according to claim 1, in which adriving signal is supplied to a plurality of transfer gates in ahorizontal transfer section in the solid-state image capturingapparatus, so that, on one side of a branching position of thehorizontal transfer section, electric charges from the vertical transfersection are transferred as necessary electric charges to a signalprocessing section positioned on one end side of the horizontal transfersection, and on the other side of the branching position of thehorizontal transfer section, electric charges from the vertical transfersection are transferred as unnecessary electric charges to an electriccharge sweeping section positioned on the other end side.
 22. A drivingmethod for driving the solid-state image capturing apparatus accordingto claim 1, in which a driving signal is supplied to a plurality oftransfer gates in a horizontal transfer section in the solid-state imagecapturing apparatus, so that, on one side of a branching position of thehorizontal transfer section, electric charges from the vertical transfersection are transferred as necessary electric charges to a first signalprocessing section positioned on one end side of the horizontal transfersection, and on the other side of the branching position of thehorizontal transfer section, electric charges from the vertical transfersection are transferred as necessary electric charges to a second signalprocessing section positioned on the other end side.
 23. An electronicinformation device comprising an image capturing section, wherein theimage capturing section includes the solid-state image capturingapparatus according to claim 1.